Remote-controlled toys



Dec. 26, 1961 c. M. ERNST 3,014,311

REMOTE-CONTROLLED TOYS Filed Feb. 18, 1957 4 Sheets-Sheet 1 1 J/VVf/WOR.

Cir/$27072 Max 5/775? Dec. 26, 1961 c. M. ERNST REMOTE-CONTROLLED TOYS 4 Sheets-Sheet 2 Filed Feb. 18, 1957 Q pafe f Agent Dec. 26, 1961 c. M. ERNST REMOTE-CONTROLLED TOYS 4 Sheets-Sheet 3 Filed Feb. 18, 1957 //V V[ N701?! Chr/sfian Max Ernsf Pant A, z

Dec. 26, 1961 c. M. ERNST 3,014,311

REMOTE-CONTROLLED TOYS Filed Feb. 18, 1957 4 Sheets-Sheet 4 7 lllllllll 763 b9 i mliln 92 7 .fA/l/f/WOR:

. Hzfenz Aj n United S The present invention relates to a remote control ap paratus, particularly for toys, smaller models, or the like, such a toy vehicles.

It is the general object of the present invention to provide a mechanism for controlling a plurality of different functions of a toy, model, or similar device from a remote point, for example, the operations of starting and stopping the driving motor of the toy or model, changing its direction of driving, and so forth.

More specifically, it is an object of the invention to provide an electrically controlled mechanism which may be operated from a remote point by electrical control impulses of different lengths to carry out different functions. 7

A feature of the present invention consists in a control mechanism of the type as above described which essentially comprises a control member, consisting of a control lever mounted on a control shaft, which is rotatable in one direction by means of electrical control impulses and is so devised that at the end of a short control impulse it automatically returns to its starting position by rotation in the reverse direction by the action of a return spring and such return movement of the control member is then utilized for carrying out a first operation or group of operations of the toy, while the transmission of longer control impulses will return the control member to its starting position by a complete revolution thereof which, in turn, is utilized to carry out a second operation or group of operations of the toy.

For attaining a proper engaging or disengaging position of the control member when long control impulses are transmitted, the present invention further proposes to move the control member until it arrives at a certain point beyond the dead-center position of its return spring, and then to arrest it at such point or engaging position by means of a stop member which is pivotable into the path of movement of the control member. When the particular control impulse is terminated, the control member then continues to turn from the engaging position to its starting position due to the force of the return spring. v

Another preferred feature of the present invention consists in providing one or more suitable coupling members between the control motor and the control mechanism which are designed so as to permit the positive connection between the control mechanism and the control motor to be automatically interrupted when a certain rotary moment is being exceeded, that is, for example, if the control member engages with a stop member which may be pivoted into the path of movement of the control member. Such coupling members may, for example, be in the form of a friction clutch which consists of one or more spring members which are positively connected to the control shaft and in frictional engagement with the driving means which are operated by the control motor.

The present invention further proposes that the stator of the control motor be pivotally mounted so that the restoring moment of the stator which is directed in reverse to the rotation of the rotor of the control motor may be utilized for pivoting the stop member into the path of movement of the mentioned control member.

A preferred embodiment of the invention further provides a resilient connection between an eccentric pin and a control lever by means of a spring wire forming a 3,014,311 Patented Dec. 26, 1 961 ice connecting rod which i pivotally connected to the eccentric pin and slidably mounted on the control lever.

The mechanism according to the present invention is especially adapted for the remote operation and control of toy vehicles which carry their own electric driving motor, as well as their own source of electric current for such motor. For operating the mechanism from a remote point, it is necessary to provide a suitable switch member, for example, a push-button switch, which is connected into the electric circuit of the control motor. By closing such switch either for shorter or longer periods of time, two different kinds of signals may be transmitted to the respective toy through the same electric wires. The apparatus according to the invention, may, however, also be used for a wireless control of toys, in which case a relay or similar device may be provided in the output stage of a wireless receiving apparatus for operating the switch in the circuit of the control motor.

Further objects, features, and advantages of the present invention will be apparent from the following detailed description thereof, particularly when read with reference to the accompanying drawings, in which FIG. 1 shows a plan view of one embodiment of the apparatus according to the invention;

FIG. 2 shows a side view thereof;

FIG. 3 shows a wiring diagram of the apparatus according to FIGS. 1 and 2;

FIG. 4 shows a view similar to that of FIG. 1 with the control mechanism in the engaged position;

FIG. 5 shows a horizontal cross section of the apparatus in the position as shown in FIG. 4;

FIG. 6 shows a plan view of a modification of the ap paratus according to the invention with its control mechanism in the released position;

FIG. 7 shows a cross section taken along line 77 of FIG. 6;

FIG. 8 shows a cross section taken along line 8--8 of FIG. 7;

FIG. 9 shows a view similar to FIG. 6 with the control mechanism of the modified apparatus in the engaged position;

FIG. 10 shows a wiring diagram of the modified apparatus according to FIG. 6; and

FIG. 11 shows a perspective view of a detail.

Although the present invention may be applied to any other toy vehicle, it has, as for an example, been illustrated in the drawings and will now be described as being applied to a caterpillar tractor or the like in which the drive shafts of both sides are driven by the same electric motor. This motor may be switched on either for for- Ward or reverse drive, and the caterpillar tracks may either both be driven for running in a straight directioii or individually for making a turn toward one side. or the other. I

Referring to the drawings, and first particularly to FlGS. l to 5, the chassis of the tractor or the like consists essentially of a sheet-metal frame 1 with an electric motor 2 secured to one of its side Walls. The shaft of the motor has a pinion 3 secured thereto which meshes with a crown gear 4 on a shaft 5 which is rotatably mounted in frame 1 and also carries a pinion 6. This pinion 6 is in mesh with a gear 7 on a shaft 8 which also carries a pair of pinions 9 and '10. Parallel to shaft 8 is a fixed shaft 11 on which two sets of gears, each consisting of an interconnected gear and pinion secured thereto, are mounted so as to be rotatable as well as inwardly slidable against the action of a spring 12. Gear 13 of one set meshes with pinion 9 on shaft 8, and its pinion 14 meshes with a gear 15 on a shaft 16 which carries a driving pinion 17 at its outer end. Similarly, gear 18 of the other set meshes with pinion 10, while its pinion 19 meshes with gear 29 on a shaft 21 which also carries a driving pinion 22 at its outer end. Frame 1 further supports a pair of slide members 23 and 24 slidable on a pin 68 for movement in a lateral direction. Slide member 23 may be moved to shift gear set 13, 14 inwardly and out of engagement with gear 15, while slide member 24 may be similarly shifted to disengage gear set 18, 19 from gear 20. Thus, either one or the other driving pinion 17 or 22 may be disengaged if the tractor is to carry out a turning movement toward one side or the other.

Aside from the electric batteries 25 indicated diagrammatically in FIG. 3, the chassis also contains an electric control switch for changing the direction of driving from forward to reverse or vice versa, and for switching off motor 2. This control switch consists of a control plate 27 of insulating material which is rotatably mounted on a shaft 26 which serves as an auxiliary control shaft and is rotatably mounted on frame 1. This control plate 27 is provided with two pairs of control contacts 28 and 29 which slightly project downwardly from plate 27. The two contacts of each pair 28 and 29, respectively, are interconnected at the upper side of control plate 27 by bridge members 30 and. 31, respectively. Underneath control plate 27, four more contacts are mounted on or formed by the ends of highly resilient spring strips 32, 33, 34, and 35. Spring strips 32 and 33 are electrically connected with the connecting terminals of motor 2, while spring strips 34 and 35 are connected to the two terminals of battery 25. FIG. 3 illustrates control plate 27 as being in one of the disconnecting positions, while in FIG. control plate 27 is shown in a connecting position by being turned at an angle of 45 about its axis relative to the position shown in FIG. 3. In this connecting position, bridge member 30 interconnects spring strips 32 and 34, while bridge member 31 connects spring strips 33 and 35 so that the electric circuit leading from battery 25 to motor 2 is closed and the latter drives the vehicle in a forward direction. When control plate 27 is again turned at an angle of 45 about its axis in a clockwise direction, the circuit from the battery to the motor will again be interrupted so as to stop the motor and vehicle, while at another turn of 45 bridge member 39 will connect spring strips 32 and 35, while bridge member 31 will connect spring strips 33 and 34 with each other. Thus it will be seen that the polarity of the current leading from battery 25 to motor 2 may be reversed so that the motor will then drive the vehicle backwardly.

The apparatus according to the invention further includes a control motor 37, the rotor of which is rotatable in a counterclockwise direction, while its freely pivotal stator is pivotable in a clockwise direction due to the restoring moment which acts upon said stator. Rotor shaft 36 of this control motor 37 extends through a cover plate 58 and carries a driving pinion 38 which is in mesh with a relatively large gear 39 mounted on a rotatable control shaft 40 which also carries a control lever 41 provided with a pin 42 thereon. A resilient return spring 44 is connected under a certain initial tension at one end to pin 42 and at the other end to a hook 43 located on frame 1. A leaf spring 67 secured to frame 1 extends into the path of movement of pin 42 and is adapted to engage therewith. Control shaft 40 also carries a gear 45 which is in mesh with a gear 46 of twice its size which is mounted on the auxiliary control shaft 26. The upper side of gear 46 carries a pin 48 in an eccentric position engaging an elongated slot 49 in a twoarmed member or control arm 50, 51 which is pivotable clutch member 57 which is secured to the upper side of rotatable control plate 27. As previously indicated, control plate 27 together with clutch member 57 are freeiy rotatable on shaft 26. Normally, the stepping mechanism defined by said clutch members 56 and 57 is engaged by the resilient pressure of spring strips 32 to 35 acting upon the lower surface of control plate 27. Frame 1 is closed at the upper side by a cover plate 58 which carries at its lower face a lever 60 which is pivotable on a pin 59 in a clockwise direction by means of a spring 61. A pin 62 secured to the freely pivotal stator of control motor 37, as shown in FIG. 5, is adapted to engage with and act upon the outer or free end of lever 60. This lever 60 is also provided with an upwardly extending lug 63 which passes through a cutout 63' in cover plate 58 and is adapted to engage control lever 41 to block the further rotation thereof when lever 60 is pivoted counterclockwise by pin 62. The upper side of cover plate 58 also supports a pair of leaf springs 64 and 65 which prevent lever 41 from pivoting in a counterclockwise direction. Finally, a remotely located switch 66 is connected in series with only a few cells of a battery 25 and control motor 37 for energizing the same. The pivotal movement of the freely rotatable stator, which may be journ'alled on the shaft of the control motor 37, upon actuation of the latter, is positively achieved by the torque created by the actuation of the motor 37 in combination with the continuous engagement of driving pinion 38 and gear 39, whereby the rotor will rotate in one direction, namely, counterclockwise. Consequently, the rotor will exert a counter moment on the stator causing the same to rotate in an opposite direction, namely, clockwise. The stator will continue to turn until the pin 62 carried thereon engages the free end of lever 60, and, finally, will be prevented from rotating further when projecting lug 63 engages the peripheral wall of cutout 63' formed in cover plate 58 through which said lug is projected. The

lug 63 is now in position to block the pivotal control lever 41, as described above.

In the second embodiment of the invention, as shown in FIGS. 6 to 11 frame 1 again supports an electric motor 2 which is adapted to drive the toy vehicle. For this purpose, a pinion 3 on the shaft of motor 2 is in mesh with a crown gear 4 on a shaft 5 which also carries a pinion 6 which is in mesh with a gear 7 on a shaft 8 so as to drive the two pinions 9 and 10. These pinions are normally in engagement with gears 13 and 18, respectively, each of which is secured to a pinion 14 or 19, respectively, and rotatable, as well as slidable with such pinion along shaft 11 against the action of a coil spring 12. Similarly as in the first embodiment, pinions 14 and 19 are in mesh with gears 15 and 20, respectively. For disengaging one or the other gear set 13, 14 or 18, 19 from pinion 9 or 10, respectively, a pair of slide members 23 and 24 is slidably mounted and movable relative to each other against the action of spring 12. A pin 68 extending through frame 1 prevents slide members 23 and 24 from pivoting relative to each other when one or the other slide member is shifted laterally so as to press one or the other gear set 13, 14 or 18, 19 inwardly against the action of spring 12 to disengage the same from pinion 9 or 10, respectively. The outer end of shaft 16 which is driven by gear 15 carries a pinion 17 which is in mesh with a sprocket wheel 70 rotatable on one end of a shaft 69, while the outer end of the other shaft 21 carries a pinion 22 which is in mesh with a sprocket wheel 71 on the other end of shaft 69. Sprocket wheels 70 and 71 serve as driving gears of a pair of endless tracks, not shown, runningover wheels 70 and 71, respectively, and a corresponding pair of sprocket wheels, not shown, at the other end of the vehicle. It will thus be evident that, when one or the other set of gears 13, 14 or 18, 19 is shifted inwardly it will be disengaged from motor 2 so that only one sprocket wheel 70 or 71 will be driven and the toy vehicle will carry out a turning movement toward one side or the other.

As shown particularly in FIG. 10, the direction of rotation of motor 2 may be reversed or its movement stopped by means of a control plate 27 which is rotatable on a shaft 26 which, in turn, is rotatably mounted in frame 1. For this purpose, control plate 27 has contact points 28 which are electrically interconnected by a bridge member 36, and contact points 29 which are interconnected by a bridge member 31. Contact points 28 and 29 are adapted to be resiliently engaged by the free end of spring strips 73, 74, 75, and 76, respectively, the other ends of which are secured to the lower surface of a plate 72 of insulating material which is secured in a fixed position on frame 1. Contact strips 73 and 74 are electrically connected with the terminals of motor 2, while contact strips 75 and 76 are connected to the two terminals of battery 25.

As further shown in FIGS. 6 to 11, a control motor 78 is mounted on control shaft 49 by means of a double lever 79 which is pivotable about shaft 46. Also shown is an arm 81 which, in turn, is pivotable about its pivot axis 89. For connecting the double lever 79 to arm 81, lever 79 is provided with a pin 77 which engages in a cutout 93 provided in arm 81. The double lever 79, as best seen in FIGURES 7, 8 and 11, maintains the axis of control motor 78 parallel to the vertically extending walls of frame 1. As a result of pivoting the double lever '79, there is imparted to the lever arm 81, via the pin 77, a similar pivotal movement about its pivot axis 86, whereby a stop member 99, carried by lever arm 81, is displaced into the path of movement of a control lever 83, the purpose of which will be described more fully hereinafter. l'hus, when switch 66 is closed to actuate control motor 73, the stator and its double lever 79 are turned in a direction counter to the rotor to thus impart the aforementioned pivotal movement to lever arm 81. Upon engagement of pin 77 against the wall of cutout 93', the aforementioned pivotal movement of double lever 79 and lever arm 81 will be terminated. For driving the control shaft 4! the same is provided with a gear 3? which meshes with the driving pinion 38 disposed on shaft 36 of control motor 78, this shaft 36 extending through an arcuate slot in frame 1. However, whereas in the first embodiment according to FIGS. 1 to 5, gear 39 is rigidly secured to shaft 40, it is in the present embodiment freely rotatable on shaft 4% and adapted to be connected therewith by means of an automatic clutch. This clutch may be of different designs but has been shown in FIGS. 6 to as being in the form of a friction clutch consisting of a cross-shaped leaf spring 82 which is rigidly secured at its center to a control lever 83 and presses resiliently upon the upper surface of gear 39. Control lever 33 which is positively connected to control shaft 46 has two arms 83 and 83" of different lengths. Arm 83" carries a pin on which one end of a coil spring 44 acting as a return spring is connected, the other end of which is connected to a pin 85 secured on frame 1. Control shaft 46 further carries and is rigidly connected to a gear 45 which meshes with a gear 46 of twice its diameter on the auxiliary control shaft 26. The upper side of gear 46 carries in an eccentric position a pin 48 on which one end of a resilient wire 86 is pivotally connected, while the wire itself is slidably connected to a control arm 87 which, in turn, is pivotably mounted about an axis 52 on frame 1. For this purpose, control arm 87 is provided with a pair of upwardly bent tabs 94, each having an aperture therein through which the connecting wire 86 is slidably inserted. Control arm 87 is further provided with a recess or cutout 53 for receiving a pair of extensions 54 and 55 projecting upwardly from slide members 23 and 24. Auxiliary control shaft 26 carries a serrated clutch member 56, the teeth of which are adapted to engage with those of the other mating clutch member 57 which is secured to control plate 27. The two clutch members 56 and 57 together form a stepping mechanism.

Finally, as shown in FIGS. 6 to 9, a pivot arm 89, which is pivotally mounted on a pin 88 on frame 1, as well as an upwardly and outwardly bent portion 90 formed on said arm 81, serve as stop members and extend into the path of movement of control member 83. Return springs 91 and 92 are provided for returning arms 89 and 81, respectively, to their starting position.

Thus, upon releasing or opening switch 66, the control impulse which causes a moment or torque acting on the stator opposite the rotation of the rotor of control motor 78, is terminated and the stator will return to its neutral position. Consequently, there ensues a return pivotal movement of the double lever 79 and the lever arm 81, due to the action of the tension spring 92, so that the stop member 93 is displaced from the path of movement of control lever 83 to free the latter for continued rotation thereof.

The operation of the entire apparatus as shown in FIGS. 1 to 5 is as follows:

If switch 66 is closed for a short length of time, control motor 37 will be energized so that pinion 38 rotates gear 39 and thereby pivots lever 41 in a clockwise direction as shown by the arrow in FIG. 1. Pin 42 will then engage with leaf spring 67 which is secured to frame 1 and thereby retard the movement of lever 41 to a certain extent. If the circuit of control motor 37 is then interrupted by switch 66 being opened, lever 41 will be returned to its initial or starting position by the action of coil spring 44. However, at such time control plate 27 will also be turned about an angle of 45 by the engagement of the stepping mechanism, namely, clutch members 56 and 57, whereby driving motor 2 will be energized by the connection of contact springs 32, 34 and 33, 35 by bridge members 36 and 31, respectively. Thus, it will be seen that by giving control motor 37 several short impulses by closing switch 66 repeatedly for a short time, the control switch 27 may be successively turned from one position to another to start motor 2 to drive forwardly, to stop its rotation, to drive in reverse, to stop, and so forth. It will thus be readily appreciated that the transmission of short impulses imparts linear movement'to the toy.

If, however, switch 66 is closed for a greater length of time, control lever 41 will overcome the holding force of springs 44 and 67 and turn in a clockwise direction until it engages against stop member 63 which is pivoted by the freely rotatable stator 37 and temporarily comes to a stop. Spring 65 projecting into the path of movement of lever 41 then prevents a return movement thereof. When switch 66 is finally released, spring 61 returns arm 66 and stator 37 to their starting position and spring 44 also returns lever 41 to its neutral position. Such movement will thus produce the following control operation.

Whenever lever 41 is in its starting position as shown in FIG. 1, and due to the fact that gears 45 and 46 have a gear ratio of 1:2, pin 48 on gear 46 will then always be in a position of holding control lever 50, 51 in its central position in which both sides of the driving mechanism are positively connected with the driving motor so that the vehicle will run in a linear or straight direction either forwardly or backwardly. However, if switch 66 is closed and lever 41 is in the pivoted position as shown in FIG. 4, gear 46 will be turned so that pin 48 will then be pivoted toward one or the other side about an angle of 90 with respect to its former position whereby either one or the other side of the driving mechanism will be disengaged from the driving motor. If, therefore, switch 66 is operated to give several longer control impulses successively, the vehicle will first drive in a straight direction, then carry out a left turn, then again drive in a straight direction, and then carry out a right turn. On the other hand, whenever control motor 37 is not energized, the vehicle will always automatically drive in a straight direction.

The principle of operation of the apparatus as shown in FIGS. 6 to 11 is similar to that of FIGS. 1 to 5 as described above. Whenever switch 66 is closed to give control motor 78 a shorter or longer current impulse, pinion 38 will drive gear 39 and clutch member 82, and thus turn control lever 83 in a clockwise direction. Only a short impulse will be required to energize motor 78 long enough to turn gear 39 about an angle of ap proximately 90.

As soon as switch 66 is released after giving such short control impulse, control lever 83 will be turned back to its starting position as shown in FIG. 6 by the tension of coil spring 44. This means that control lever 83 then carries out a turning movement in the counterclockwise direction and that control plate 27 then carries out a rotary step-by-step movement through clutch members 56 and 57.

If switch 66 is operated to give longer control impulses, control lever 83 wili likewise turn in a clockwise direction and, after its arm 83" has pivoted past arm 89, it engages with stop member 95 on arm 31, as indicated in dot-anddash lines in FIG. 9. After such engagement, the automatic clutch formed by spring 32. due to slippage disengages the connection between the freely rotatable driving gear 39 and control member 83. Thus, if very long control impulses are given, shaft 36 of control motor 78 may continue to rotate, while control lever 83 will be prevented from rotating by engaging with stop member 91 Spring 82 forming the friction clutch and secured to control lever 83 then slides along the fiat surface of gear 39. When the control impulse is terminated, control lever 83 is freed from stop 90 and is further turned by coil spring 44 until it arrives in its starting position. Gear 46 turns about an angle of about 90 at each half turn of control shaft 40. Since pin 48 will then also be turned about an angle of 90, the resilient wire 85 will pivot control lever 87 to the position as shown in FIG. 9 whereby one or the other slide member 23 or 24 will be shifted laterally and the driving gears of the vehicle at one or the other side thereof will be disengaged from the driving motor and its gears. Thus, by giving several long control impulses successively, control arm 87 will be pivoted back and forth and the vehicle will first be driven straight ahead, then in a left turn, then again straight ahead, then in a right turn, and so forth. The resiliency of the connecting wire 86 permits gear 39 to carry out its rotary movements even though control arm 87 is in a pivoted position as shown in FIG. 9. At such time wire 86 will bend and thus permit gear 46 to turn. As a result of the bending of the connecting wire 86, there is made possible rotational movement of the gears 39 and 46, irrespective of the position of control arm 87.

The present invention is not restricted to the particular embodiments as above described and illustrated in the accompanying drawings and various modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Having thus described my invention, what I claim as new is:

1. An electrically driven toy having a pulse-actuated control mechanism for controlling the direction of travel of the toy, comprising, in combination: an electric drive motor; an electric control motor; a switch in circuit with said control motor; a rotatable control disk driven by said control motor; biasing means operatively associated with said disk and effective up to a half rotation for urging said disk in a rotational direction opposite to that in which it is driven by said control motor; switch means in circuit with said driving motor for reversing the polarity thereof, thereby to reverse the direction of rotation thereof; transmission means interposed between said disk and said switch means for actuating the latter only when the former rotates in said opposite direction; separate propulsion means for movirrg said toy; a transmission system interposed between said propulsion means and said drive motor, said transmission system including disengageable transmission members for selectively deactivating said propulsion means; a mechanical control member for controlling said transmission members; motion transmitting means for transmitting movement of said control disk to said mechanical control member; blocking means and disengageable rotation-preventing means operativcly associated with said disk for blocking return movement as well as driven rotation of said disk after the same has rotated half a revolution; and operating means interposed between said control disk and said control member for moving said control member into a position wherein it causes one of said disengageable transmission members to deactivate the corresponding propulsion means only when said control disk is rotated an angular distance of more than 2. A toy as defined in claim 1 wherein said mechanical control member is a pivotally mounted lever having two arms of different lengths.

3. A toy as defined in claim 1 wherein said control motor comprises a stator and a rotor, and means for pivotally mounting said stator, the torque of said stator being directed opposite to the direction of rotation of said rotor.

4. A toy as defined in claim 1 wherein said switch means in circuit with said driving motor comprises a plate rotatably mounted on said toy, and a stepping mechanism for actuating said switch means.

5. A toy as defined in claim 1 wherein said control member is a pivotally mounted lever and wherein said operating means comprise a pin arranged eccentrically relative to said control disk and received in an elongated slot of said lever.

6. A toy as defined in claim 5 wherein there are at least two of said propulsion means which are arranged at both sides of said toy, wherein said transmission means comprise a driving gear driven by said drive motor and at least two driven gears adapted to engage with said driving gear and connected with said two propulsion means, respectively, and wherein said lever is connected for selectively disengaging said driven gears from said driving gear.

7. A toy as defined in claim 6 wherein said lever is a two arm lever, one of said arms being formed with said slot receiving said pin and the other of said arms being adapted to engage said driven gears.

8. A toy as defined in claim 7 wherein said lever is so constructed and arranged that when it is pivoted by said pin in one direction, one of said driven gears is disengaged from said driving gear so that said toy is driven only on one side, that when said lever is piv oted back to its neutral position, said one driven gear is reengaged with said driving gear so that said toy is driven at both sides, and that when said lever is pivoted by said pin in the opposite direction, the other of said driven gears is disengaged from said driving gear so that said toy is driven only on the other side.

References (Iited in the file of this patent UNITED STATES PATENTS 2,422,117 Mercier June 10, 1947 2,519,472 Howard Aug. 22, 1950 2,679,712 Schwien et al. June 1, 1954 FOREIGN PATENTS 998,830 France Sept. 26, 1951 

